Distance Covered represents the total distance covered by a defender from the time the bat makes contact with the ball until the moment he fields it. This metric only takes into account the route actually traveled by the fielder -- NOT the direct route from the fielder's starting position to the ball. (In fact, if you divide a player's optimal route to the ball by his Distance Covered, you get another Statcast metric called "Route Efficiency.")
Distance Covered can be a fascinating metric, but only when given proper context. For instance, if an outfielder covers 100 feet to make a catch -- it's far more impressive if he does so in four seconds than if the ball hangs in the air long enough for him to do so in seven seconds.
In A Call
"range covered," "ground covered"